There’s a moment to savour in the 1930 Marx Brothers comedy Animal Crackers when Groucho flings woo at two wealthy women while wishing he could tell us what he really thinks of them. ‘Pardon me while I have a strange interlude,’ he says, stepping out of the scene to deliver a solemn monologue in a hollow, faraway voice:

Here I am talkin’ of parties. I came down here for a party. What happens? Nothing. Not even ice-cream. The gods look down and laugh. This would be a better world for children if the parents had to eat the spinach.

Eugene O’Neill’s Strange Interlude, written in 1923, was a four-hour psychodrama acclaimed for its modern use of soliloquy and unflinching approach to adultery, madness and abortion. That the Marx Brothers could so ruthlessly spoof O’Neill’s recently established theatrical trademark – along with those poetic non sequiturs, the invocation of indifferent deities, a whiff of the ineffable beneath the hokey vernacular and the doom-laden register – tells us plenty about the cultural range and tolerances of 1930s cinema audiences, the Marx Brothers’ hair-trigger sensitivity to intellectual pretension, the giddy extent of the 42-year-old playwright’s celebrity and, finally, something about O’Neill’s writing itself.

The weaknesses, then